This invention relates to a rapidly quenched ribbon magnet and a plastic magnet containing powders of the rapidly quenched ribbon magnet.
Among the rare earth element-iron-boron base alloys for permanent magnets, there is known a sintered magnet of a neodymium-iron-boron base alloy. This alloy material has drawn public attention because the materials for the alloy are available more easily than the samarium-cobalt base alloy for permanent magnets while being rather inexpensive and of higher performance characteristics. Also known are a sintered magnet of an iron-boron base alloy containing a rare earth element derived from didymium, and a ribbon magnet of a neodymium-iron-boron base alloy.
There is also known a plastic magnet containing magnet powders obtained by pulverizing a rapidly quenched ribbon magnet of a neodymium-iron-boron base alloy or a rapidly quenched ribbon magnet of a praseodymium-iron-boron base alloy.
However, problems are presented in the industrial mass production of the elements neodymium and praseodymium as the starting materials for the rapidly quenched ribbon magnet of the neodymium-iron-boron base alloy or the praseodymium-iron-boron base alloy because the complicated and expensive production process is involved in the preparation of these elements, while it has not been possible to produce these elements with fully satisfactory magnetic properties. In addition, in the case of these known rapidly quenched ribbon magnets, a heating process has been required to perform after the manufacture of the ribbon magnets in order to evolve their magnetic properties, with correspondingly increased production costs.